• C API includes header and source files that enable a DLL to access Excel 2010 functionality, and a description of the interface that a DLL should expose to work with the Excel Add-in Manager.
• Microsoft Visual Studio 2008 projects includes C/C++ source code and shows how to use the C API.
• Documentation includes the API function reference, conceptual, and how-to Help topics.

In conjunction with Microsoft Excel 2013, the Microsoft Excel 2013 XLL Software Development Kit (SDK) includes support for the following new features:

• New Functions The Microsoft Excel 2010 XLL SDK supports calling back to all of Excel 2013's new worksheet functions.